Chicago—In a finding that illustrates the stark realities of modern warfare, a military trauma study has shown that soldiers who sustained chest injuries in Operation Enduring Freedom in Afghanistan and Operation Iraqi Freedom had higher mortality rates than soldiers in Korea, Vietnam and Bosnia.

The finding surprised many surgeons who heard the results presented at the 2012 Clinical Congress of the American College of Surgeons (ACS). The results were, in the words of one surgeon, “counterintuitive.”

The investigators said that the results may be explained by advancements in other areas of battlefield care, namely triage and transport systems. Severely wounded soldiers who would have been killed in action in previous conflicts are more likely to survive in today’s wars and be sent to trauma centers in the United States.

“We feel that these findings are likely a reflection of our ability to get more severely injured soldiers, who otherwise may have died on the battlefield, to a medical facility,” said Capt. Katherine M. Ivey, MD, a resident in general surgery at San Antonio Military Medical Center, who presented the study.

Dr. Ivey and trauma surgeons from the U.S. Army Institute of Surgical Research in Fort Sam Houston, Texas, compared mortality rates from chest injuries in conflicts dating back to the Civil War, when 63% of such injuries resulted in death compared with 10% in World War II, 2% in Korea and 3% in Vietnam. In the wars in Iraq and Afghanistan, the rate of mortality from chest injuries rose to 8.3%—9.2% in Afghanistan and 6.2% in Iraq.

The investigators said that advances in prehospital care, rapid transport and protective equipment for combat personnel may have resulted in more severely injured patients arriving alive at a field hospital or other medical facility, which contributed to increased mortality after admission.

The researchers focused on injuries of the thorax and analyzed data from the Joint Theater Trauma Registry for U.S. soldiers who sustained a chest injury in Iraq and Afghanistan from January 2003 to May 2011. The analysis did not include soldiers killed in action.

Of 2,049 chest injuries analyzed in the two conflicts, 70% occurred in Operation Iraqi Freedom. The most common thoracic injuries were collapsed lung, pulmonary contusions and rib fractures. Most chest injuries were caused by penetrating trauma (61.5%), followed by blunt trauma (26.7%) and blast injuries (11.6%). In just over two-thirds of cases, the injured soldiers died in the operating theater.

It is impossible to isolate a single cause of the high mortality rates from chest injuries, said John S. Ikonomidis, MD, PhD, Horace G. Smithy Professor and chief of cardiothoracic surgery, Medical University of South Carolina, Charleston. He moderated the ACS session during which the study was presented.

“I find it hard to believe that it was a problem with technology and availability of medical care. But for whatever reason, there has been a bit of a concerning—concerning to me—increase in mortality.

“I have to wonder if there has been a change in the trend of warfare and the trend of artillery that may have contributed to this. Certainly, we can see that these blast injuries are very bad. This may serve as a cause to have our military consider blast injuries and take steps to equip our troops to be more protected from them,” he said.

Helicopters and fixed-wing aircraft have long played a role in evacuating battlefield wounded. But in the Iraq and Afghanistan wars, the army has acquired the ability to move wounded patients to higher-level care centers in the United States “within days or weeks of injury as opposed to weeks or months,” the investigators said.

In all, 1,412 operations were performed at combat support hospitals, which are modern military field hospitals that provide a range of surgical and medical specialties and have ICUs.

The study did not analyze specific transport factors that contributed to improved survivability of battlefield wounded. The investigators did not analyze why soldiers fighting in Iraq experienced a higher rate of chest injuries than in other wars.